Opening 27 files

Have a problem opening a .27 file? We collect information about file formats and can explain what 27 files are. Additionally we recommend software suitable for opening or converting such files.

What is the .27 file type?

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The most common occurrence of numerical extensions like .27 is related to versioned project files saved by Pro/Engineer, a highly complex and extremely powerful parametric Computer-Aided Design (CAD) software by PTC. Pro/Engineer encompasses CAD solutions dedicated to a range of different industries and areas of application.

To maintain a consistent workflow and allow traceability, Pro/Engineer routinely saves backup copies of each project, before any changes are actually committed. Each backup copy receives an additional numerical extension (like .27), to indicate the file's version. Thus, the .27 file is the twenty-seventh copy of a Pro/Engineer working file.

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Pro/Engineer keeps track of versioned backups, and files with extensions like .27 can be opened and manipulated the same way as regular Pro/Engineer projects.

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Quite differently, appearance of the ".27" character string in place of a filename extension often relates to the original extension being missing or concealed. If the ".27" string takes up a trailing position within a filename (e.g., to indicate the file's position in a series), it could easily become a technical extension, if the original extension is somehow removed.

On Microsoft Windows, extensions for the known file types are concealed by default (the "Hide extensions..." option in Windows Explorer), which can cause dotted strings like .27 to falsely appear as extensions. To avoid confusion, the "Hide extensions..." options should always be turned off.

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Apart from that, numerical extensions like .27 are commonly assigned to each part of split files in a sequential order, starting from 0. A split file is a large single file broken into multiple parts that can be losslessly rejoined later. For instance, extensions like .27 are used by the freeware Hacha file splitting tool.